Eric Wesoff is Editor-at-Large at Greentech Media. Prior to joining GTM, Eric Wesoff founded Sage Marketing Partners in 2000 to provide sales and marketing-consulting services to venture-capital firms and their portfolio companies in the alternative energy and telecommunications sectors. Mr. Wesoff has become a well-known, respected authority and speaker in these fields.

His expertise covers solar power, fuel cells, biofuels and advanced batteries. His strengths are in market research and analysis, business development and due diligence for investors. He frequently consults for energy startups and Silicon Valley's premier venture capitalists.

Vivint Solar's CEO Tanguy Serra has "stepped down as CEO" and will remain with the company as an advisor. Alex Dunn has replaced Serra as CEO. Vivint was recently acquired by Blackstone for $2 billion.

Darren Kimura, founder and once-CEO and chairman of Sopogy, has been moved to the role of Chief Global Strategist and CMO of the startup, which is looking to commercialize smaller-scale concentrating solar power (CSP). David Fernandez, formerly a VP at SunEdison, has been named President and COO.

In a long-expected exit, Cathy Zoi has left her investor seat at Silver Lake Kraftwerk to join Tom Siebel's C3 as its CSO. (This move was spotted by GigaOM.)

The Switch, a builder of megawatt-class permanent magnet generators and full-power converter packages for wind and other renewables, named David Zhao as GM for China. The firm claims to have provided its equipment for 6.5 gigawatts of wind installations.

BuildingIQ, a building energy management software firm focused on commercial HVAC, added Greg Brewer as VP of sales and Adam Benson as VP of engineering.

Marathon Capital added David Kirkpatrick as Director. Kirkpatrick's energy experience includes stints at GE, EDF-EN/enXco, and NRG Solar. Marathon Capital is an investment bank focused on global energy and infrastructure, particularly the North American renewable energy markets.

Climate scientist Dr. James Hansen retired as head of NASA’s Goddard Institute of Space Studies. Hansen pegged 350 ppm of CO2 as the safe ceiling for carbon in Earth's atmosphere. Here's an interview with Hansen fromSustainability Media about leaving NASA, the climate, and his next move.